Large-volume containers are often used for holding, storing, and transporting bulk materials, such as powders, agriculture leaf and root crop products, metal castings, plastic resins, and many other materials. Generally, the containers provide sturdy walls that protect the bulk materials from entry of pests and from container failure while allowing the containers to be handled by equipment such as fork lift trucks and platen or clamp trucks. The containers are also often stacked in warehouses.
One type of container useful for holding bulk materials assembles from corrugated paperboard blanks. A first blank defines the exterior walls and a second blank defines the interior walls. The laminated blanks fold on the scores and attach at opposing ends to define a tubular body having a cavity for holding the bulk materials. The exterior blank includes flaps that fold to form a bottom.
Bulk leaf products typically are filled through tubes that enter the container and withdraw as the container fills. A ram forces the leaf products into a block having high density and under compression within the container. The leaf products contain moisture, and the block starts expanding as the ram withdraws. Top flaps on the container fold to close the container. A plurality of straps generally spaced on approximately 6 inch intervals down the length of the container tighten and secure to prevent the top and bottom from opening to reveal the contents of the container. The filled containers are placed in stacks in warehouses for the leaf products to dry. After a period of time, the leaf product is removed for processing, and the container is typically re-used up to five times depending on the quality of the container after use.
The leaf products within the container however expand and press forcingly against the walls, bottom and top of the bulk materials container. Notwithstanding the straps, this expansion leads particularly to the top flaps buckling or bulging. The bulging tops have the potential for causing a stack of containers to tip, and a container that falls or a stack that tips over can cause injury to persons as well as loss of the product if the container bursts open because of the fall.
In addition, the corrugated inner liner has an open edge of exposed corrugated channels. As the leaf product fills the container, some dust, particulates, portions of leaves and stems may enter the channels. This is not satisfactory due to the re-use of the containers.
Accordingly, there is a need in the art for a bulk materials container that provides improved bulge resistance for stacking and restricts lodging and infiltration of particulates into the walls of the container. It is to such that the present invention is directed.